The present invention relates to a means for preventing the operation of a locking mechanism until a ball has been successfully moved through a labyrinthic passageway. Several devices have been developed that employ a ball to lock or unlock two or more interconnected members. Examples of such devices include those disclosed by La Montagne U.S. Pat. No. 3,650,379, Hein U.S. Pat. No. 2,709,357, Maclaren U.S. Pat. No. 2,499,765, and Frederiksen U.S. Pat. No. 698,486. The most pertinent of these known prior art devices is that disclosed by Frederiksen as comprising a rotatable labyrinthic enclosure through which a ball may be encouraged, by rotation of the enclosure, to move until arriving at a position where it may be employed, by a separate and distinct operator-exerted force, to unlatch an associated locking mechanism. The remaining three prior art devices each employ one or more balls as obstructing elements to prevent the separation of interconnected members until the balls have been moved to predetermined positions within the device.